1. Field of the Invention
The present invention relates to a female metal terminal in which, when a male metal terminal is fitted into this female metal terminal, a resilient contact piece portion is resiliently contacted with the male metal terminal to guide the same so as to stabilize the contact thereof with the male metal terminal, thereby preventing the increase of contact resistance so as to stabilize the electrical connection.
The present application is based on Japanese Patent Application No. Hei. 11-171618, which is incorporated herein by reference.
2. Description of the Related Art
FIGS. 5 to 7 show a conventional female metal terminal disclosed in Unexamined Japanese Patent Publication No. Hei. 8-250174.
In FIGS. 5 to 7, the female metal terminal 1 includes a metal terminal body 3 of a box-shape, having an insertion port 2 for inserting a terminal portion 20 of a male metal terminal therethrough, and a resilient contact piece portion 5 formed by folding that portion of a bottom plate 4 of the metal terminal body 3, extending from an end of the insertion port 2, back into the interior of the metal terminal body 3. The resilient contact piece portion 5 includes a flexing portion 6, bent into the interior of the metal terminal body 3 at the lower side of the end of the insertion port 2, a slanting portion 7 extending obliquely rearwardly from the flexing portion 6 within the metal terminal body 3, and a resilient support portion 8 which extends from a distal end of the slanting portion 7, and is curved toward the bottom plate 4, and is resiliently held against the bottom plate 4.
When the male metal terminal is inserted into the female metal terminal 1, a distal end of the terminal portion 20 of the male metal terminal is brought into resilient contact with the slanting portion 7, so that an inserting resistance is produced. When this inserting operation is completed against this inserting resistance, the terminal portion of the male metal terminal is held in resilient contact with contact portions 9, formed on an apex portion of the slanting portion 7, thereby securing a predetermined contact load.
A slit 10 is formed in the resilient contact piece portion 5, and extends from the proximal end thereof, connected to the bottom plate 4, toward the distal end thereof in a direction of insertion of the terminal portion 20 of the male metal terminal. Each of the flexing portion 6, the slanting portion 7 and the resilient support portion 8, is divided by this slit 10 into two sections in the direction of the width of the resilient contact piece portion 5.
The resilient contact piece portion 5 is thus divided into the two sections by the slit 10. With this construction, when the distal end of the terminal portion 20 of the male metal terminal is inserted in inclined relation to the resilient contact piece portion 5, and is brought into contact with the resilient contact piece portion 5 at one side portion thereof, that section of the resilient contact piece portion 5, with which the distal end of the terminal portion 20 of the male metal terminal first comes into contact, is resiliently deformed in a larger amount to undertake a larger proportion of the inserting force of the terminal portion 20 of the male metal terminal. Therefore, the inserting resistance can be reduced as compared with a construction in which the inserting force is received by the whole of a resilient contact piece portion of a single platelike construction.
The resilient contact piece portion 5 is divided into the two sections by the slit 10 as described above, and in this connection, the two contact portions 9, which contact the terminal portion 20 of the male metal terminal when the insertion of this terminal portion 20 is completed, are formed respectively on the apex portions of the two sections of the slanting portion 7. When the insertion of the terminal portion 20 of the male metal terminal is completed, the resilient forces of the two sections of the resilient contact piece portion 5 act on this terminal portion 20 through the respective contact portions 9, and therefore the large contact load can be secured.
In this conventional metal terminal, when the terminal portion 20 of the male metal terminal is inserted into the female metal terminal 1 through the insertion port 2 as shown in FIG. 6, the distal end of the terminal portion 20 of the male metal terminal is first brought into contact with the slanting portion 7 of the resilient contact piece portion 5 of the female terminal 1. When the male metal terminal, thus contacted with the slanting portion 7 of the resilient contact piece portion 5, is further inserted, the distal end of the terminal portion 20 of the male metal terminal, is guided by the slanting portion 7, and slides over this slanting portion 7 to advance within the female metal terminal 1 while pressing the resilient contact piece portion 5 toward the bottom plate 4. Then, this distal end abuts against the contact portions 9 formed on the apex portion of the slanting portion 7. When the terminal portion 20 of the male metal terminal is further inserted, with its distal end thus abutted against the contact portions 9, the distal end of the terminal portion 20 shaves surface portions of the contact portions 9 or almost the whole of the contact portions 9.
When even the surface portions (part) of the contact portions 9 are thus shaved by the distal end of the terminal portion 20 of the male metal terminal, there is encountered a problem that the contact of the contact surfaces of the contact portions 9 becomes unstable, and this unstable contact invites the increase of the contact resistance, so that the electrical connection becomes unstable.
It is an object of the present invention to provide a female metal terminal in which contact portions, formed on an apex portion of a slanting portion of a resilient contact piece portion, will not be shaved by a distal end of a male metal terminal, and the contact of the male metal terminal with the contact portions is stabilized so as to prevent the increase of a resistance of contact between the contact portions and the male metal terminal, thereby stabilizing the electrical connection.
To achieve the above object, according to the first aspect of the present invention, there is provided a female metal terminal which comprises a metal terminal body having a bottom plate and an insertion port which is formed in one end portion of the metal terminal body, and through which a male metal terminal is insertable into the metal terminal body, a resilient contact piece portion formed within the metal terminal body, the resilient contact piece portion including a flexing portion formed by folding back an extending portion of the bottom plate of the metal terminal body from the insertion port into an interior of the metal terminal body, a flat portion extending rearwardly from the flexing portion within the metal terminal body, and a resilient support portion extending from a distal end of the flat portion, curved toward the bottom plate, and held against the bottom plate, wherein the resilient contact piece portion is partially divided into a plurality of sections so as to divide the flat portion into a plurality of sub-flat portions, and a plurality of contact portions respectively formed on at least two of the sub-flat portions disposed at opposite side portions of the resilient contact piece portion, the contact portions being extended along upward portions and downward portions of the at least two of the sub-flat portions, the downward portions located downwardly from a position against which a distal end of the male metal terminal can abut when the male metal terminal is inserted into the metal terminal body, wherein the contact portions are respectively formed in a band-like manner obliquely relative to an insertion direction of the male metal terminal.
With this construction of the female metal terminal, the distal end of the male metal terminal will not shave the contact portions, and the contact of the contact portions with the male metal terminal is stabilized, and the resistance of contact of the contact portions with the male metal terminal is prevented from increasing, thereby stabilizing the electrical connection.
According to the second aspect of the present invention, more specifically, the sub-flat portions having the contact portions may be inclined so that the upward portions are upwardly located than the downward portions, respectively. In this construction, one of the contact portions may be extended from a right side portion of one of the upward portions to a left side portion of one of the downward portions, and the other one of the contact portions may be extended from a left side portion of the other one of the upward portions to a right side portion of the other one of the downward portions.
According to the third aspect of the present invention, the contact portions may be arranged gradually away from each other toward distal end portions of the contact portions on the downward portions from distal end portions of the contact portions on the upward portions. Alternatively, according to the fourth aspect of the present invention, the contact portions may be arranged gradually away from each other toward distal end portions of the contact portions on the upward portions from distal end portions of the contact portions on the downward portions.
According to the fifth aspect of the present invention, it is preferable that the resilient contact piece portion is partially divided into at least three sections by slits, and the resilient support portion has, at a distal end portion thereof, a connecting portion which interconnects between at least two of the sections formed by dividing the resilient contact piece portion. With this construction of the female metal terminal, when the distal end of the male metal terminal is inserted, the plurality of divided sections of the resilient contact piece portion separated from each other, are prevented from being resiliently deformed independently of each other. Therefore, the resistance of contact of the contact portions with the male metal terminal is prevented from increasing, thereby stabilizing the electrical connection.
According to the sixth aspect of the present invention, it is preferable that the slits are formed in the flexing portion, the flat portion and at least a part of the resilient support portion of the resilient contact piece portion. In this construction of the female metal terminal, the slits are formed not only in the flat portion, with which the male metal terminal can come into direct contact, but also in the flexing portion, and therefore the sub-flat portions can be resiliently deformed more independently of each other during the insertion of the male metal terminal, so that the inserting resistance can be reduced.
According to the seventh aspect of the present invention, it is preferable that at least two of the sub-flat portions, on which the contact portions are formed, include the upward portions each having an inclination angle smaller than an inclination angle of each of the downward portions relative to the bottom plate of the metal terminal body. With this construction, the amount of shaving of the contact portions by the distal end of the male metal terminal is reduced.
Further, according to the eighth aspect of the present invention, the distal end portion of the resilient support portion may be divided by at least one slit. Incidentally, the resilient contact piece portion may be partially divided in a direction substantially perpendicular to the insertion direction of the male metal terminal.